Lubricated valve



Patented June 16, 1942 UNITED STATES PATENT OFFICE H LUBRICATED i George F. Scherer, San Eranci sco, Calif as- -I signor to Merco Nordstroiii valve .Companm; Pittsburgh, Pa", a corporation :oi' Delaware Application .iul ie, 194 Serial No. 402,595 -s claims. -(ci.i2s-1-9s)' This invention relates to lubricated plug valves, particularly of the tapered jacking type.

In lubricated plug valves, particularly of that type having a chamber at one end of the plug to receive lubricant under pressure for moving the' plug longitudinally, difficulty in turning the valve sometimes is encountered, and this difliculty is condition is especially liable to occur in tapered "valves having a separate operating stem controlled by a one-way valve which does not allow lubricant to pass therethrough intothe chamber but which allows any higher pressure from said chamber to act upon the lubricant at the smaller end of the plug. The pressure in the lubricant chamber may fall below lineipressure due to a of the chamber, and in certain types due to escape of lubricant along the stem or longitudinal movement of the stem, and I believe that the difficulty heretofore encountered was due to the relatively.

not overcome upon lubrication of the valve. This cover plate |8 held in place at its margin by studs and nuts I9. g

The casing It] has an extension 2| at the smaller end of the bore through which a threaded hole 22 extends, and a threaded operating stem 23 extends through said hole into the chamber I6 at the small end of the plug. The operating stem 23 is separate from the plug l3 and'has a tongue or extension 24 fitted into a suitable recess 25 in the small end of theplug, the fit bein loose enough to provide for a slight play or lost 1 motion. 01', if desired, an adapter of the Oldhamcoupling type may be used to provide a connection between the stem and plug. The stem 23 has an accurately machined running thread which co-operates with the threads in the wall of-hole 22 in the extension 2| of the casing. Be-' formed in the extension 2| surrounding the hole 22 andis adapted to be packed with a suitable j lubricant or fibrous packing material to provide number of causes, such as temperature expansion high pressure difference acting on the plug to wedge it into its seat when the pressure of the lubricant in the jacking chamber was reduced for any reason. This theory is confirmed by the observation that themore perfect the fit between the plug and seat, the more frequently is this difficulty encountered, as apparently line pressure cannot enter the well sealed jacking chamber.

The invention will be described in. detail in connection with the accompanying drawing, where--.

in I have illustrated a preferred embodiment of the invention by way of example, and wherein the figure represents a'vertical cross sectional view of a valve.

Referring to the drawing, the invention comsageway II for fiow of line fluid therethrough. Also formed within the casing and extending transversely of the passageway II, is a bore |2 the end of the plug, the casing walls and the 'packing thereto.-

The plug I3 .is adapted to be rotated in its seat to opened or closed position by the segmental worm gear 26, suitably secured to the operating stem 23, and co-operating worm 21 secured on shaft 38, the latter shaft being rotatable by a hand. wheel (not shown) secured thereto or by other suitable means. The extension 2|" of the casing has a flange 28 thereon to which is secured a casing 3| through a leak-proof connection as shown for housing the gearing mechanism for operating the plug For supplying lubricant to the seating surfaces of the-plug and casing and for jacking the plug,

' from its seat, the stem 23, which extends exprises a body or casing l0 provided with a pasv temally of the casing 3|, has a hole 32 drilled and tapped therethrough in which is located a screw 34 for developinglubricant pressure. Suitable ball check valve fittings 35 in the hole 32 prevent escape of lubricant or line fluid when the screw is removed for refilling. The hole 32 extends the whole way through the stem so as to provide communication'through the stem, and through recess 25 with the lubricant chamber It at the smaller end of the plug; The seat|2 has two diametrically opposed dwarf or short connecting grooves 38 communicating with the chamber I6 and with two pairs of vertical lubricant grooves 38 in the surface of the plug. The

grooves 38 are disposed on the plug so that in the full open or closed positions thereof they'comr municate with the connecting grooves 36 and with the ends of the circumferential grooves 39 and 4| respectively at the larger end of the plug. The grooves 3'! communicates in all positions with the chamber l6 and with the ends of circumferential grooves 39 and M at the large end of theplug, and are not exposed to the passageway through the valve in turning the plug between open and closed positions. The ends of grooves 39 and 4! may be spaced substantially 90 apart. For jacking the plug from its seat by lubricant pressure, the screw 34 is advanced into the stem, thereby introducing lubricant into the The cover-l8 is inherently resilient and it is formed preferably as a steel forging or a steel casting of suitable thickness. A gasket 43 of aluminum or. other suitable material is located on a suitable shoulder surrounding the seat I2 at the large end of the plug, and a diaphragm 44 is located on this washer and is clamped betweenthe gasket and the cover I8. The diaphragm 44 may be single, but preferably is composed of two plates, the internal plate being preferably a non-corrosive alloy such as 18-8 stainless steel, the other or external diaphragm being composed of carbon steel having the proper physical characteristics. The plug has a recess 45 in its large end in which is located a steel ball 46, and a thrust disc 41 having a suitable recess therein is located between the ball l and diaphragm 44., Recess 45 may communicate with the plug port M, or if desired, anadditional bore may be provided connecting chamber IT with the plug port ii. The cover I! has a threaded bore 48 therein adapted to receive the adjusting screw 49, this bore being counterf- A steel thrust disc 52- is located in this counterbore and is adapted to be pressed against the diaphragm by the adjustment screw IS. The adjustment screw 49 may be covered by a combined lock nut and cap 53 which preferably is spot welded to the cover to prevent access to screw 49. When it becomes necessary to adjust the screw 49, this cap can be broken loose from the weld by a pipe wrench.

Under certain conditions of operation sometimes encountered in service, the plug may become stuck in its seat so as to be extremely diflicult or even impossible to release by the jacking action of lubricant pressure. While ordinarily the pressures acting longitudinally-on the plug are substantially equal so that the end thrust of the plug is due only to differential areas. conditions may arise under which the pressures become unequal.- Thus, a relatively small 'loss of lubricant 'from chamber It may cause theis arranged to allow flow from chamber ll to chamber IS, but Prevents flow of lubricant from chamber l8 to chamber 11.

From the foregoing description it will be aparent that if the pressure in chamber l6 falls for any. reason, the check valve 56 allows line fluid pressure from chamber I! to enter and equalize the pressure therein before any binding or wedging of the plug can occur.

Having described my invention, what I claim and desire to secure by United States Letters Patent is:

1. A valve comprising a casing having a passageway therethr'ough for flow of fluid and a 1 seat extending transversely of the passageway,

a plug located in said seat and having a port adapted to connect with said passageway in open' position of the valve, said plug and casing providing chambers at opposite ends of the plug, means for supplying lubricant under pressure to one of said chambers. a duct not connected with the plug surface connecting said chambers and' tion of the valve, said plug and casing-providing chambers at'opposite ends of the plug, means for supplying lubricant under pressure to one of said chambers, a duct connecting the other of bored to provide a shoulder '51 [at its interior.

' other chamber to the lubricant system and preplug into its seat. When this occurs, the plug can be packed by lubricant only ficultyb -According to my invention, I overcome this with great difdifllcalty by connecting chamber l1 directly with chamber through a. duct. 55 having a one.-

51 threaded into bore 55 and having a ball 58 way or check valve.56 therein of suitable con- 1 struction. Valve 56 preferably comprises a sleeve said chambers to the port in the plug, a duct not connected with the plug surface connecting said chambers, and a valve in said duct permitting ilow from said last mentioned chamber to the first mentioned chamber and preventing how in the opposite direction.

3. A valve comprising a casing having a passageway therethrough for flow of fluid and a seat extending transversely of the passageway, a plug located in said seat and having aport adapted to connect with said passageway in open position of the valve, said plug and easing providingchambers at opposite ends of the plu means for supplying lubricant under pressure to one of said chambers, a lubricant groove system in the seating surface of the plug and seat includinggrooves exposed to line pressure in certain positions and connected to said one chamber in unexposed positions, a duct not connected with the plug surface connecting the other of I said chambers with the lubricant system, and a valve in said duct permitting flow from said venting flow in the opposite direction.

4. A valve comprising a casing having a passageway therethrough for flow of fluid and a tapered seat extending transversely of the pas-' sageway, a tapered plug located in said seat and providing a lubricant chamber with the casing at the smaller end thereof, an operating stem for rotating said plug, a cover for closing one end of the seat, means for resiliently maintaining said plug on its seat, and providing a chamseat extending transversely of the passageway,

a plug located in said seat, and providing a lubricant chamber with the casing at one end thereof, an operating stem for rotating said,

plug, a cover for closing one end of the seat 6 flow from the second chamber to the lubricant l chamber and preventing flow in the opposite direction.

6. A valve comprising a casing having a passageway therethrough for flow of fluid and a seat extending transversely ofthe passageway,

formed by the plug and casing adjacent said stem, a chamber formed by the plug and casing opposite the stem end of the plug, means for supplying lubricant under pressure tothe chamher at the stem end, a duct not exposed to line fluid connecting said chambers, and a one-way valve in said duct permitting flow into the stem and chamber and preventing flow in the opposite direction.

7. A valve comprising a casing having a passageway therethrough for flow of. fluid and a tapered seat extending transversely'of the passageway, a tapered plug located in said seat and having a port adapted to connect with said passageway in open position of the valve, an o crating stem at the smaller end of the plug sep-' arate therefrom, said plug and casing providing a lubricant chamber adjacent the stem end'of the plug, means for'supplying lubricant under. pressure to the lubricant chamber, a second chamber at the opposite end of the plug, a duct not exposed to line fluid connecting said chambers, and a one-way valve in said duct permitting flow into the lubricant chamber and preventing flow in the opposite direction.

'8. A valve comprising a casing having a passageway therethrough for flow of fluid and a tapered seatextending transversely of the passageway, a tapered plug located in said seat and having a port adapted to connect with said passageway in open position of the valve, an operating stem at the smaller end of the plug separate therefrom, said plug and easing providing a lubricant chamber adjacent the stem,

a chamber formed at the opposite end of the plug, means for supplying lubricant under pressure to the lubricant chamber, a lubricant system forthe seating surface of the plug and seat and including said first mentioned lubricant chamber, a duct connecting said lubricant system with the'chamber at the larger end, and a valve 'in said duct permitting flow from said large end chamber to the lubricant system and preventing flow in the opposite direction.

' GEORGE F. SCHERER. 

